Dharanidhar Maddali

• Maddali, Dharani Dhar; Solvin, Håvard Bjerkeseth; Lippert, Matthias; Karabiyik, Yücel; Dahle, Gry & Hjelmervik, Jon Mikkelsen [Show all 9 contributors for this article] (2024). Monte Carlo-based rendering of 3D echocardiography for mixed reality-guided atrial septal puncture positioning. Computer Assisted Surgery. 29(1). doi: 10.1080/24699322.2024.2403444. Full text in Research Archive Show summary

  Catheter-based intervention procedures contain complex maneuvers, and they are often performed using fluoroscopic guidance assisted by 2D and 3D echocardiography viewed on a flat screen that inherently limits depth perception. Emerging mixed reality (MR) technologies, combined with advanced rendering techniques, offer potential enhancement in depth perception and navigational support. The study aims to evaluate a MR-based guidance system for the atrial septal puncture (ASP) procedure utilizing a phantom anatomical model. A novel MR-based guidance system using a modified Monte Carlo-based rendering approach for 3D echocardiographic visualization was introduced and evaluated against standard clinical 3D echocardiographic display on a flat screen. The objective was to guide the ASP procedure by facilitating catheter placement and puncture across four specific atrial septum quadrants. To assess the system’s feasibility and performance, a user study involving four experienced interventional cardiologists was conducted using a phantom model. Results show that participants accurately punctured the designated quadrant in 14 out of 16 punctures using MR and 15 out of 16 punctures using the flat screen of the ultrasound machine. The geometric mean puncture time for MR was 31 s and 26 s for flat screen guidance. User experience ratings indicated MR-based guidance to be easier to navigate and locate tents of the atrial septum. The study demonstrates the feasibility of MR-guided atrial septal puncture. User experience data, particularly with respect to navigation, imply potential benefits for more complex procedures and educational purposes. The observed performance difference suggests an associated learning curve for optimal MR utilization.

• Engelsen, Peder Christian Grendstad; Heyerdahl, Fridtjof; Maddali, Dharani Dhar; Akhavi, Medhi Sadat; Undseth, Ragnhild Marie & Elle, Ole Jakob [Show all 7 contributors for this article] (2023). Ascending with ultrasound: telementored eFAST in flight—a feasibility study. Emergency Radiology. ISSN 1070-3004. 31, p. 25–31. doi: 10.1007/s10140-023-02186-x. Full text in Research Archive Show summary

  Abstract Purpose Teleultrasound uses telecommunication technologies to transmit ultrasound images from a remote location to an expert who guides the acquisition of images and interprets them in real time. Multiple studies have demonstrated the feasibility of teleultrasound. However, its application during helicopter flight using long-term evolution (LTE) for streaming has not been studied. Therefore, we conducted a study to examine the feasibility of teleultrasound in an Airbus H145 helicopter. Methods Four anesthesiologists and one military physician were recruited to perform telementored extended Focused Assessment with Sonography in Trauma (eFAST) during nine helicopter flights, each with a unique healthy volunteer. A radiologist was recruited as a remote expert, guiding the physicians in their examinations. The examining physicians reported the user experience of telementored eFAST on a questionnaire, while the remote expert rated the diagnostic quality of the images on a 1–5 Likert scale. In addition, we measured the duration of the examinations and key LTE network parameters including signal strength, quality, and continuity. Results The images were rated to an average of 4.9 by the remote expert, corresponding to good diagnostic quality. The average duration of telementored eFAST was 05:54 min. LTE coverage was negatively affected by proximity to urban areas and ceased above 2000 ft altitude. Occasional audio problems were addressed by using the Voice over LTE network for communication. The examining physicians unanimously reported on the questionnaire that they would use telementored eFAST on patients. Conclusion Telementored eFAST is feasible in ambulance helicopters and can produce images of good diagnostic quality. However, it relies on stable LTE coverage, which is influenced by many factors, including the helicopter’s altitude and flight path. Furthermore, its benefit on patient outcomes remains to be proven. Graphical abstract

• Maddali, Dharani Dhar; Brun, Henrik; Kiss, Gabriel; Hjelmervik, Jon M. & Elle, Ole Jakob (2022). Spatial Orientation in Cardiac Ultrasound Images Using Mixed Reality: Design and Evaluation. Frontiers in Virtual Reality. 3. doi: 10.3389/frvir.2022.881338. Full text in Research Archive Show summary

  Spatial orientation is an important skill in structural cardiac imaging. Until recently, 3D cardiac ultrasound has been visualized on a flat screen by using volume rendering. Mixed reality devices enhance depth perception, spatial awareness, interaction, and integration in the physical world, which can prove advantageous with 3D cardiac ultrasound images. In this work, we describe the design of a system for rendering 4D (3D + time) cardiac ultrasound data as virtual objects and evaluate it for ease of spatial orientation by comparing it with a standard clinical viewing platform in a user study. The user study required eight participants to do timed tasks and rate their experience. The results showed that virtual objects in mixed reality provided easier spatial orientation and morphological understanding despite lower perceived image quality. Participants familiar with mixed reality were quicker to orient in the tasks. This suggests that familiarity with the environment plays an important role, and with improved image quality and increased use, mixed reality applications may perform better than conventional 3D echocardiography viewing systems.

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• Engelsen, Peder Christian Grendstad; Heyerdahl, Fridtjof; Maddali, Dharani Dhar; Akhavi, Mehdi Sadat; Undseth, Ragnhild Marie & Elle, Ole Jakob [Show all 7 contributors for this article] (2024). Correction to: Ascending with ultrasound: telementored eFAST in flight—a feasibility study (Emergency Radiology, (2023), 31, 1, (25-31), 10.1007/s10140-023-02186-x). Emergency Radiology. ISSN 1070-3004. 31(4), p. 629–629. doi: 10.1007/s10140-024-02265-7. Full text in Research Archive

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